In our daily life, ventilation systems such as air-conditioners are commonly provided in working or living spaces, e.g., office buildings and apartments, for supplying fresh outdoor air and exhausting polluted indoor air simultaneously in order for keeping a favorable and healthy environment where we stay. Generally, the outdoor air and the indoor air have different temperatures and humidities. In this connection, a significant effect of energy saving could be expected if the exchange between the indoor and outdoor airflows can be achieved not only in heat but also in moisture. In order to satisfy such requirements, total heat exchange apparatuses, which can exchange sensible heat (temperature) and latent heat (moisture) simultaneously without mixing up different types of air, are accordingly developed. Total heat exchange apparatuses are effective in energy saving as they can recover both sensible energy (temperature) and latent energy (moisture) between polluted indoor air and fresh outdoor air.
Referring to FIG. 13, an embodiment of a rotary total heat exchanger for conducting total heat exchange between the indoor air and the outdoor air is shown. The heat exchanger includes a rotary wheel 1 defining a plurality of mini air channels 2 therein, for increasing heat conduct areas thereof. The wheel 1 is covered with heat exchange materials having better heat conductivity and moisture permeability for increasing the heat exchange rate of the wheel 1. The wheel 1 is divided by a plate 5 into two portions separately positioned in an air-outlet housing 3 and an air-inlet housing 4. The wheel 1 is driven to rotate through the air-outlet and air-inlet housings 3, 4 by a driving motor 6, to perform heat exchange between the outdoor and indoor air. The indoor and outdoor air pass through the air channels 2 of the wheel 1 in a counter flow manner. When the wheel 1 rotates beyond 180 degrees, the wheel 1 originally stationed in the air-outlet housing 3 revolves to the air-inlet housing 4, and the wheel 1 originally stationed in the air-inlet housing 4 revolves to the air-outlet housing 3, conducting a total heat exchange of heat and moisture between the indoor air and the outdoor air. With the rotation of the wheel 1 through the air-outlet and air-inlet housings 3, 4, the indoor and outdoor air frequently exchange heat and moisture to ensure that the outdoor fresh air entering in the room has a needed temperature and moisture for satisfying a requirement of the indoor air quality.
Total heat exchange apparatuses are effective in keeping indoor air quality, as well as in energy saving, as is identified above. However, in order to exhibit its full advantages, many improvements still can be made on the design of a total heat exchange apparatus. For example, as far as a rotary total heat exchange apparatus is concerned, the exchange of heat and moisture between different airflows is conducted only in its rotary wheel 1 by resorting to the heat-conductivity and moisture-permeability capabilities of the heat exchange materials of the wheel 1, which results in a limited sensible heat exchange rate as the materials typically have its focus placed on the capability of moisture-permeability rather than heat-conductivity. Also, when the indoor and outdoor air pass through the wheel 1, the mini channels 2 of the wheel 1 may be blocked by dust taken by the air. The blocked mini channels 2 decrease the heat exchange rate of the wheel 1, and furthermore may function as a bed for bacillus to grow, which is harmful to the health of people and reduces the indoor air quality. So the indoor and outdoor air need to be filtrated before entering the mini channels 2 of wheel 1.
Moreover, the supplied air and the exhausted air to be heat-exchanged are typically directed by blowers. The airflows provided by the blowers flow in a direction which does not enable the airflows to flow evenly over mini channels 2 of the wheel 1 in the total heat exchange apparatus. This greatly impairs the total heat exchange efficiency of heat and moisture between the supplied air and the exhausted air.
In view of the above-mentioned problems of the total heat exchange apparatus, there is a need for a total heat exchange apparatus which can improve the sensible heat exchange effect between different airflows conducting heat exchange in the total heat exchange apparatus to increase the indoor air quality, and what is also needed is a total heat exchange apparatus which can distribute the air currents to be heat-exchanged more evenly over the air channels of its total heat exchange member.